This Is A New Goodman 3.5 Ton Heat Pump System Installed In July 2013. During Th

This is a new Goodman 3.5 ton heat pump system installed in July 2013. During the cooling season it worked fine.Last night I set the honeywell TH6110D1005 thermostat on the HEAT setting set at 70 degrees set on HOLD set to HEAT and the fan set to AUTO. Overnight I awoke at 2:00 AM and was very hot so I checked my thermometers and found the actual home temperature was 79 to 80 degrees all around. I then checked the thermostat and the setting temperature read 70 degrees and the thermometer on the thermostat was reading 70 degrees which was clearly inaccurate.However, the heat pump was running continually and had been running continually for hours.I reset the on temperature to 68 degrees and the heat pump stopped running. In the morning the temperature reading was still 70 degrees and all other thermometers were reading 66 to 68 degrees. I reset the on temperature at 71 degrees and it came on and seemed to be working.The next night it was set on HOLD set to HEAT and the fan set to AUTO. The temperature was set to 71 degrees. At 1:30 am the outside temp was 34 degrees and the indoor temp was 78 degrees. The air output from the farthest register was 116 degrees when checked which was most likely the emergency electric heater working. The temperature reading on the thermostat was 71 degrees and the set temperature was 71 degrees.Once again the thermometer reading on the thermostsat was stuck and not reflecting the true temperature of the home. My confidence in this thermostat's performance is now reduced. What if this happens and I'm not home for several days? What could cause the thermostat to show and hold an innacurate house temperature and keep running even when both the temperatures on the thermostat reads 70?I would have expected the system to at least stopped when both temperatures are the same.